PDF file format, developed by Adobe Systems, represents in electronic mode all the elements of a printed document such as text, photos, links, scales, graphs and interactive elements. You can view this document in free Acrobat Reader, navigate through the page or the whole document which is one or more pages usually. PDF format is used to save predesigned magazines, brochures and flyers. Whenever you need to view it, print or send the layout will be unchangeable.